The present invention relates to an open-end spinning unit of the type having a break-up roller arranged to be coaxial with the spinning rotor. This break-up roller receives rovings from a feed roller and breaks the rovings up into individual fibers, the feed roller being immediately ahead of the break-up roller or being connected thereto through the intermediary of a feed channel.
In open-end spinning units having break-up rollers which are arranged to be coaxial with the spinning rotor, the individual fibers are known to be fed into the spinning rotor in the form of a bell-shaped veil. The fibers thus enter over the entire periphery of the spinning rotor, i.e. during the yarn formation process newly fed-in individual fibers are continuously added to the yarn and are bound into it to a greater or lesser degree in dependence on the time of the yarn formation. Consequently, certain properties of the yarn being formed vary in a periodic manner, this being true, in particular, of its roughness.
The problems of adding individual fibers into the spinning rotor have already been discussed in German Auslegeschrift [Published Patent Application] No. 1,111,549. The spinning unit disclosed in this publication is provided with a stationary fiber guide disc disposed in front of the spinning rotor. A narrow space is provided between the surface of the fiber guide disc and the inner bottom surface of the spinning rotor and the yarn formed in the fiber collecting trough of the spinning rotor is guided through this space. The fiber guide disc thus produces sufficient separation between the fibers shooting into the fiber collecting trough and the yarn extracted therefrom.
German Offenlegungsschrift [Laid-Open Application] No. 2,064,697 further discloses an open-end spinning unit having a break-up roller which is arranged to be coaxial with the spinning rotor and which is also provided with a fiber guiding service. This device presents a substantially radial annular gap which is formed, on the one hand, by a fiber guide edge provided at the break-up roller and, on the other hand, by the suitably designed housing edge of the break-up roller housing.